Gear-cutting machine.



cLA. PARSONS, 'A Q- CARNEGIE & s s. COOK.

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GEAR CUTTING MACHINE.

APPLICATION FILED MAR. 2. IIJIG.

' Patented Aug. 6, 1918.

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CHARLES ALGERNON PARSONS AND ALFRED UPON-TYNE, AND STANLEY SMITH COOK, OF CARNEGIE ANI} SAID COOK ASSIGNORS TO SAID PARSONS.

QUINTIN CARNEGIE, OF NEWCASTLE- WALLSEND, ENGLAND; SAID GEAR-Corrine MACHINE.

Specification of Letters Patent.

Original application filed March 25, 1913, Serial No. 756,762. Divided and this application filed March 2, 1916. Serial No.81,740.

To all whom it may concern:

Be it known that we, the Honorable Sir CHARLES ALGERNON PARSONS, K. C. B.,'AL- FRED QUINTIN CARNEGIE, both subjects of the King ofGreat Britain and Ireland, and residing at Tyne, in the county of Northumberland, England, and STANLEY SMITH Coon, a subject of the King of Great Britain and Ireland, and residing at Turbinia Vorks,

WVallsend, in the county of Northumberland,

' with a high order of accuracy, a still higher degree of accuracy is desirable to insure the silent operation otmgear wheels when transmitting large powers at high speeds, and also to minimize the wear of the teeth. It is obvious that with the processes already adopted the accuracy of the finished wheel cannot be greater'than that of the parent gear of the machine by which the teeth are cut. Local irregularities in this parent g ear vcause irregularities in the teeth of the wheels being out which exactly correspond in angular position with those of the parent gear, and which, when such wheelsa re in opera tion for the transmission of power, will give rise to periodic vibrations, often of high Frequency, and therefore productive of noise.

In the case, for instance, in which the table on which the work is mounted is rotated by means of a worm and a worm wheel, the latter being attached permanently to the table, it will be seen that the irregularities formed on the work are a function of the angular position of the table in relation to the position of the worm. The lat ter is usuallyfixed and since the cutter is also usually in a fixed position on the machine, and advances across the work in a direction parallel to the axis of the table, there will result lines of irregularities on the finished wheel lying in planes through the Heaton WVorks, Newcastle-uponrelative rotational motion of the wheel and pinion engaging therewith. If, however, a small amount of rotary motion relative to the table be imparted to the work it will be' seen that the irregularities formed in the work will be distributed spirally around the wheel, and that if this relative creep be considerable, these spirals will make a small angle with the plane'of revolution of the wheel, and will consequently lie closely to each other, with the result that the pinion and wheel will, when geared together, preserve a constant relative angular velocity be tween them.

The present invention consists in improved nieans for distributing the irregul arities formed in the work in spirals making a comparatively small angle with the plane of revolution of said work, whereby the periodic correspondence of said irregularities with the irregularities of the parent gear rotating the same is destroyed. Referring to the accompanying draw- 1ngs:

Figure 1 is a cross sectional elevation through the work carrying table and aceompanying parts of a gear cutting machine that Fig. 3 does to Fig. 1 as stated above.

Fig. 5 is a sectional view looking from left of Fig. 3. e

In carryingthe invention, into .efi'ect, ac-

cording to the present construction, a primary table 1 is provided, constrained to rotate' about its axis by a bearing 2, in the bed member 3. table 1 is an indexing worm wheel 4, with Patented Aug. 6, rate.

Attached to the primary tion for shitting which a driving worm stituting a parentgear.

Upon the primary table 1 a secondary table 6 "s rotatably mounted, and is held O engages, these conl \vn to the table 1 by dogs the work 8 mounted upon the secomlary table 6, in any suitable manner.

The liTiQtl spindle 9 carries a gear wheel 10, which operates a train. of spurs 11, 12, 13 and 1.4-, and pinions l5, 16, 17 and 18, mounted upon the prin'iary table 1, the last wheel lit gearing; withan annular wheel 19, mounted. concentrically,upon the secondary table i5 and rigid. therewith and at least one intermediate member of the train being mounted on the index wheel or primary table 1.

I t will be seen that the movement of the train of wheels about the stationary pinion. causes the former to revolve. and to 0pcrate upon-the annular wheel 19 attached to the secondary table 6, which thus given a motion relatively to the primary table 1, the amount of such motion depending upon the proportions adopted in the gearing.

It will be understood that the shaft 20 is driven from any suitable source of power, and so connected in. any well known manner with. the hob drive and cutter 'leed mechanism that the proper relations are maintained to produce the required pitch of the teeth cut on the work. and also the helical angle of the teeth when helical teeth are requirel to be cut.

Referring to Figs. 3 and 4 which illustrate the connections betweenthe work table and the hob drive and hob, it is to be noted that these connections may be the smile as those described in the Letters Patent granted. to us as above referred to. The machine is driven by an electric motor (1/, which drives through suitable gearing the spindle b, from which motion is transmitted through suitable c ange speed gearing, c, to the shaft, (Z. onion is also transmitted from the n'iotior a, through the sbait. d, to a cross shaft and gear wheels 7, and through a reversing gear. to the spindle, 72 The gear wheels, f, form a change" o'er r by which the helical a ngle of the teeth formed on the work is con trolled through the usual differential .in shaft :1. The shaft 6 is a part of a connecreversing gears at g, said shat't being operated by the hand lever 16*. The spindle, 7), carries a bevel. wheel, 2', gearing with another bevel wheel, j, mounted on a vertical spindle, /'a, mounted in the cutter standard. l. The vertical spindle, 7c, is provided with a feather-way m, by which its rotation is transmitted to the cutter. The spindle, ii, is provided with a worm, n, which engages with a worm wheel, 0, on another vertical spindle, ya, mounted in the cutter standard, Z. This spindle, p, is threaded, and when rotated causes a vertical up or down movement of the cutter, thus moving the cutter across the face of the work. The cutter standard, 7, is provided with suitable means for being traversed longitudinally on the bed, I oi. the machine by means ot' the threaded spindle, 1*, which can be rotated by the hand wheel, 8.

The rotation of the shaft, (6, is transmitted director through suitable compensating gear, as shown at 235, 2%, 25, and as will be hereinafter described, to a bevel wheel, 25, engaging with another bevel wheel, u, on a horizontal shaft, a, carrying" at its other end another bevel. wheel, 0). This engages with yet a further bevel wheel, .11:, on a vertical shaft, y, carrying at its other end a worm, .2, engaging with a worm wheel, 1, on a shaft 2*, provided with the worm 5.

Having now described our invention, what we claim as new and desire to secure byLe-tters Patent is 1. A helical gear cutting machine comprising in combination a primary table, a parent gear rotating said table having a driving; and driven. member, said driven member being attached to said primary table, a secondary table on which the work is carried. mounted on said prin'iary table, a train of gearingmounted on said primary table and caused to rotate by the motion thereof, said train of gearing being connected to said secondary table and causing, said secondary table to rotate at a different rate from the primary table, means to rotate said parent gear, a hob, means to rotate said hob, means between said hob rotating means and said parent gear rotating means to preserve the correct indexing relation between the rotations of said hob and the rotations of said secondary table, means to feed said .hob, and means between said hob feeding means and said parent 'ear rotating means to preserve correct lead relation between said hob teed and the speed of said secondary table.

2. A helical gear cutting machine eomprising in combination a primary table, a parent gear rotating said table having a driving and driven member, said driven member being attached to said prin'iary table, a secondary table on which the work is carried 'mounted on said primary table, a train of toothed wheels mounted. upon said primary table, the first of said toothed wheels ongaging a statioi'iary pinion coaxial with said tables, the last of said toothed wheels engaging internal teeth carried by said secondary table, whereby the train of gearing is caused to rotate by the motion of the primary table and to rotate the secondary table at a ditl'erent rate vfrom the primary table, n'ieans to rotate said parent gear, a hob, means to rotate said hob, means between said hob rotating means and said parent gear rotating means to preserve correct indexing newness 8 relation between the rotations of said hob and the rotations of said secondary table means to feed said hob, and means between said hob feeding means and said parent gear rotating means to preserve correct lead relation between said hob feed and the speed of said secondary table.

3. A helical gear cutting machine com-. prising in combination a rotatable work carrying table, an index wheel, means to rotate said index wheel, a gear train, certain elements of the'said train being mounted u on said index wheel, means to position the, rst memberof said train coaxial with said index wheel and stationary relatively thereto, the final member of said train being connected to said table, a hob, means to rotate said hob, means between said hob rotatingin'eans and said index wheel rotating means/to preserve correct indexing relation betweeii the rotations of said hoband the rotations of said work-carrying table, means to feed said hob, means between said hob feed'iig means and said index wheel rotating'il cans to preserve correct lead relation between said hob feed and the speed of said table.

A gear cutting machine comprising in combination a rotatable Work-carrying table, anindex wheel,- means to rotate said index,

wheel,.a gear train, means to prevent the rotation of the first member of said train, the final member of said train being, connected to said table, and an intermediate member of said train being connected to said i1 ilex wheel, a hob, means to rotate said hob, means between said hob rotating means and said index wheel rotating means to preserve correct indexing relation between the rotations of said hob and the rotations of said table, means tofeed said hob and means be.- tween said hob feeding means and said index wheel rotating means to preserve correct lead relation between said hob feed andthe speed of said table.

5. A gear cutting machine comprising in combination a work-carrying member'adapted to rotate about an'axis, an index wheel rotatable about the same axis, means to rotate said index wheel, a gear train of toothed wheels, means to hold the first pinion of said train stationary and coaxial with the axis of said index wheel, means coaxial with said member to connect the last wheel of said train to said member and means upon said index wheel to rotatably support at least one intermediate wheel of said train, a hob, means to rotate said hob, means between said hob rotating means and said index wheel rotating means to preserve correct indexing relation between the rotations of said hob and the rotations of said work-carrying member, means to feed said hob, and means between said hob feeding means and said index wheel rotating means to preserve correct lead relation between said hob feed and v the speed of said work-carrying member.

6. A gear cutt ng machine comprising in combination a work-carrying table rotatable said index wheel rotating means to'preserve correct indexing relation between the rotations of said hob and the rotations of said work-carrying member, means to feed said hob, and means between said hob feeding' means and said index wheel rotating means to preserve correct lead relation between said hob feed and the speed of said work-earl ing member.

In testimony whereof we have aflixed our signatures.

CHARLES ALGERNON masons. ALFRED QUIN'IIN CARNEGIE. STANLEY SMITH 000x. 1, 

